A pneumatic fender is used, for example, when transferring crude oil between two adjacent ships, the pneumatic fender is installed between the two hulls to prevent contact between the hulls. Alternatively it is installed on a quay wall or the like, to prevent contact between the quay wall or the like and a ship's hull. In recent years ships' hulls are getting larger and the sea conditions are becoming more severe, so there is a demand for large (large diameter) pneumatic fenders with excellent impact performance.
Pneumatic fenders normally have a cylindrical-shaped body portion with bowl-shaped mirror-sections provided at both ends, and the body portion has a laminated configuration with a plurality of reinforcing layers between inner layer rubber and outer layer rubber. The reinforcing layers are cord layers formed by arranging a plurality of cords in parallel, and the cords are disposed at a predetermined cord angle with respect to the axial direction of the cylinder. The cords of reinforcing layers that are laminated adjacent to each other are disposed so that they intersect (for example, see Japanese Unexamined Patent Application Publication Nos. H5-286053, 2003-129446). Conventionally the cord angle is set to a static angle of about (54° to 55°) in an uninflated neutral state, so even when the interior of the pneumatic fender is filled with air to the prescribed internal pressure, its size (length and external diameter) does not change much.
In this case, if the pneumatic fender is simply made larger in order to increase the impact performance, its handleability when it is not being used, such as in storage, transport, and installation, is significantly reduced. Specifically, wide space is needed to store the pneumatic fender. Also, a large transport ship is necessary to transport it to its place of installation, and the lifting device such as a crane or the like must also be large. Also, during transport and installation it is difficult to move, so much effort is required. Therefore a pneumatic fender that is compact when not being used, and that greatly expands as much as possible when it is being used is desirable.